Manufacture of lead tubes and cable sheaths



sotheannularchamber' Patented Oct. 30, 1934 PATENT OFFICE mum-across or LEAD 'ru'rms AND cams: snm'rns Georg Zapi, Colosnc Germany, assiznor .to

Felten & Gnilleaume Carlswerk Aktiengesellschait, Cologne-Mulhcim, Germany Application April 20,

' In Germany 1Claim.-

a press block in which the lead is conveyed fromthe receiver to the annular chamber surrounding the mandrel through a narrow passage and two channels which are disposed on either side of the annular chamber and are connected with one another by the narrow passage. Below the mandrel the two lead streams meet one another at an obtuse angle and form a seam in the lead sheath, for instance as shown in Fig. 1.

The lead oxides which-form when 'the molten lead is being poured into the receiver and are deposited in or at the seam of the lead sheath during the pressing-operation hinder the satisfactory welding of the latter. This fact which is well known to those skilled in the'art easily causes cracks to form in or close to the seam of the sheath.

In the manufacture of welded tubes it is known that the overlapped welded seam is superior as 2b regards its strength and tightness to the butt- 'welded joint. With this experience in view the invention has for its object to manufacture a pressed'tube in whichinstead of the butt-welded joint shown in Fig. 1 an overlapped welded joint ,30 according to Fig. 2 is formed. The lead oxides which in the press heads as hitherto used accumui late min joint are distributed i the overlapped iolntin such a manner that they no longer hinder'the forming of a satisfactory joint. According to the invention the overlapped joint can be produced by the channels of the annular chamher being caused to converge in such a'manner below the mandrel thatthe lead streams flowing through them overlap one another as they enter Pigs. 8 to 5 a constructional example of a press block according to the invention in three different sections, the press block being shown inl'lg. 1 in horizontal section andin Figs. 4 and dintwoverticalsections'a- Bandc-D. The

1934, Serial No. 121,631

March 31, 1933- lines of flow indicated in the drawing represent the direction of flow of the lead in the different parts of the press head, the left hand and right hand half and the overlapping and overlapped part of the lead stream. being shown diflerently.

In the drawing a is the receiverorgate with a cylindrical bore and b the press block.'- The bore of the receiver emerges at c into anarrow passage d of a kind known per se, which on all sides surrounds the mandrel e lying at right angles to it and opens at all sides into the annular chamher surrounding the mandrel e. The ring a forms together with the mandrel e the outlet opening of the press block for the pressed tube. Forenabling the lead in the annular chamber to be guided below the" mandrel in two streams overlapping one another, the cross-section of the narrow passage 11 is widened laterally and at the bottom to form channels hand i, the latter being so arranged that they lie one behind the other without a dividing wall below the mandrel and form a chamber 7:: of about double the cross secvtional area of one channel. The chamber 1: opens at the top into the narrow passage d. The vcross-sectional dimensions of the lateral and bottom widening of the channel 11 depend on the condition that a uniform pressure drop and conthe mandrel in overlapping manner so as to cause the lead streams flowing through them to overlap one another where they enter the annular chamber.

. GEORJG ZAPF. 

